JPS6127950Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stretching device for stretching raw hide, such as cowhide, used as a material for power transmission belts, into leather having a uniform thickness.

Conventionally, a device as shown in FIG. 1, for example, has been used to stretch raw hides. That is, in FIG. 1, reference numerals 1 and 2 represent a pair of plates, to which are fixed a number of clips 3 that engage the edges of the raw hide. Then, the raw hide 4 to be stretched is supported between the plates 1 and 2 by hooking its edges 5 and 6 to clips 3 corresponding to each edge, and then the plates 1 and 2 are held together. It was pushed in the direction of separation (in the direction of arrows A and B), and the raw hide 4 was stretched.

In such a conventional device, the clip 3 is connected to the raw hide 4.
Because it is attached at a certain distance to the
There is a disadvantage that a uniform stretching force is not applied to the raw hide 4, and therefore uniform elongation cannot be expected unless the raw hide has a uniform thickness and a rectangular or square planar shape.

This drawback can be solved by, for example, determining the position of the clip through precise calculations according to the thickness distribution and planar shape of the raw hide, and by taking into account the direction of movement of the board. Although it may be possible to solve the problem, it is impossible to apply it to mass production, and it would require a lot of experimentation as it would have to target all raw hides of all planar shapes, and it would be difficult to solve the problem from a cost perspective. I have to say that such a method is impossible to implement.

The purpose of the present invention is to provide a leather stretching apparatus that solves the disadvantages of the conventional apparatus and simultaneously dehumidifies the raw hide during the stretching operation of the raw hide. , two easily stretchable rubber sheets with high frictional force on the inner surface are overlapped, and while the raw skin is inserted and supported between them, the polymer of the rubber sheet with the raw skin inserted inside is placed on a workbench with its entire periphery. by fixing the rubber sheet polymer in one direction and curving it, stretching the raw skin together with the rubber sheet, and forming at least one side of the rubber sheet from a porous material. This is characterized by the fact that the moisture leaked from the raw leather during stretching is absorbed by the rubber sheet to remove moisture from the raw leather.

Examples will be described with reference to the drawings.

In Figures 2 to 4, reference numerals 11 and 12 are rubber sheets having a square or rectangular planar shape, which are easily stretchable and made of a material with a high frictional force on at least the inner surface, and at least on the lower side. The rubber sheet 12 located at is made of a sponge-like porous material having the above-mentioned properties.

Then, both rubber sheets 11 and 12 are overlapped with each other, and the raw skin 13 to be stretched is inserted between them (see FIG. 2). In addition, a tube 14 connected to a vacuum source (not shown) is provided at the insertion point of the raw skin 13, and when the vacuum source is activated, both sheets are
The polymerization of Nos. 1 and 12 is made stronger, and the raw skin 13 is firmly held on its entire surface by both rubber sheets (see Fig. 3).

Next, the entire periphery of the polymer of the rubber sheet (the polymer has the raw skin 13 sandwiched therein) is fixed with the fixture 21 on the workbench 20, and the rubber sheet 12 is placed near the center of the lower rubber sheet 12. A pressing force is applied from below, for example, by a hydraulic ram device 22, and the pressing force bends the rubber sheet polymer into an arched shape as shown in the fourth figure. (Since FIG. 4 is a cross-sectional view, the curve due to the pressing force is shown in an arched shape, but it is clear that the rubber polymer curves three-dimensionally into a spherical shape.)

In this way, when the rubber polymer with the raw hide sandwiched inside is pressed so that the rubber polymer curves into a spherical shape by a pressing force from the outside, the entire periphery of the rubber sheet is fixed. , the rubber sheet is stretched. At this time, since the raw hide is held between the rubber sheets and the inner surface of the rubber sheet has a large amount of friction, the raw hide 13 is also stretched at the same time as the rubber sheet is stretched.

When this raw hide is stretched, the tensile force acts on the entire surface of the raw hide, so that the raw hide is stretched by the action of a uniform stretching force, and extremely ideal raw hide stretching is achieved.

At this time, since the raw hide is also subjected to the pressing action of the rubber sheets 11 and 12 inside thereof, (most of) the water contained in the raw hide is squeezed out by this pressing force. This squeezed out water is absorbed into the pores of the rubber sheet, so
Stretching and dehumidification of the raw hide will be achieved simultaneously.

Note that if the rubber sheet located on the lower side is made porous, the dehumidifying effect of the raw hide will be even more remarkable.

As mentioned above, in the present invention, the raw hide is sandwiched between two rubber sheets, and the rubber sheet is stretched by applying a pressing force that causes the rubber sheet to curve into a spherical shape.
Since the raw hide is stretched by stretching this rubber sheet, it is possible to apply a uniform stretching force to the entire surface of the raw hide, and by using a porous rubber sheet, the water squeezed out from the raw hide is absorbed. However, the dehumidification of the raw leather can be achieved at the same time as the stretching of the raw leather, and the practical effects of the present invention are remarkable.

In the above description, the term "rubber sheet" is not limited to those made of natural rubber or synthetic rubber, but refers to materials similar to those made of rubber in terms of elasticity, frictional force, flexibility, etc. Of course, it refers to sheets made of all materials that

[Brief explanation of the drawing]

Figure 1 is a plan view of a conventional leather stretching device, Figure 2-
FIG. 4 is a sectional view of the leather stretching device according to the present invention. 11, 12...Rubber sheet, 13...Hide, 2
0... Workbench, 21... Fixture, 22... Hydraulic ram device.

Claims (1)

[Scope of utility model registration request] Two rubber sheets that are easy to stretch and have a large frictional force at least on their inner surfaces are stacked together, a thick skin is inserted between the two rubber sheets, and a communication pipe that communicates with a vacuum source is provided at this location. The entire periphery of the polymer is engaged with a fixture that fixes it to the workbench, and a device is provided that applies a pressing force to the outer center of one of the rubber sheets. At least one piece of leather is a stretching device made of a porous material such as a sponge.